Suspension system liquid oxygen converter



April 1961 G. F. HAWK ET AL 2,981,434

SUSPENSION SYSTEM LIQUID OXYGEN CONVERTER Original Filed Aug. 17, 1956 2Sheets-Sheet 1 By M; fiaehmm/ V' M ATTORNEYS.

April 25, 1961 s. F. HAWK EI'AL 2,981,434

SUSPENSION SYSTEM LIQUID OXYGEN CONVERTER Original Filed Aug. 17, 1956 2Sheets-Sheet 2 /a as 38 42 34 ATTORNEYS.

United States Patent 9 SUSPENSION SYSTEM LIQUID OXYGEN CONVERTER GaleFrederick Hawk and George S. Kiester, Bryan, Ohio, assignors to The AroEquipment Corporation, a corporation of Ohio Original application Aug.17, 1956, Ser. No. 604,744. Divided'and this appiication Oct. 19, 1959,Ser. No. 847,338

Claims. (Cl. 220-) This invention relates generally to improvements incontainer suspension systems and more particularly to improvements insuspension systems for thermally insulated containers of the typeadapted to store liquid oxygen and the like. This application is adivision of our co-pending application Serial No. 604,744, filed August17, 1956, and now Patent No. 2,924,351.

The requirements for containers of the type adapted to hold and storelow temperature materials are relatively stringent. For example, incontainers for converter systems utilizing liquid oxygen-such as may befound in apparatus used as a source of breathing oxygen in aircraftdesigned for high altitude flightresistance to heat loss should be ashigh as is practically obtainable. Further, the containers should berelatively sturdy with high resistance to vibration, shock and othermechanical disturbances. Still further, such containers advantageouslyshould be relatively light weight, compact, eificient, ca-.

pable of holding a vacuum and economical to manufacture and use. Liquidoxygen containers of the prior art have not proved entirely satisfactoryin meeting these requirements, and consequently there has existed a needfor a new type of liquid oxygen container.

' It is a general object of this invention to provide an improvedcontainer and, in particular, an improved container for holding andstoring liquid oxygen and the like.

' It is another object of this invention to provide an improved vacuumcontainer which has high resistance to heat loss and therefore iscapable of storing liquid oxygen for substantial periods of time withoutundue vaporization.

It is still another object of this invention to provide an improvedliquid oxygen container which is characterized by its efficiency, lightweight and high resistance to injury from'vibration, shock and similarmechanical disturbances.

It is a further object of this invention to provide such an improvedliquid oxygen container, as above, having an inner shell for storingliquid oxygen suspended within an outer shell, the space between the twoshells being evacuated to a high degree, and the outer shell beingformed of two spherical segments and an equatorial central band adaptedto support a plurality of uniformly spaced arcuate suspension beamstherearound for minimizing the mechanical contact between the inner andouter shells.

These and other objects are realized in accordance with the featuresembodied in specific illustrative embodiments of this invention in whichan inner shell suit- .able for use with liquid oxygen and the like issuspended within an outer shell with a practical minimum of mechanicalcontact therebetween, and with the space between the two shells capableof being evacuated to a relatively high degree. Advantageously, theinner shell is in the form of a sphere to provide minimum surface areafor a given volume. Manifestly this results in providing minimum forceon the internal surface of the inner ice shell for a given gas pressuretherewithin. The outer or protective shell advantageously is also in theform of a sphere, but is of larger radius than the container such thatthe inner shell is completely enclosed by the outer shell. The inner andouter shells, hereinafter referred to as the inner and outer spheres,respectively, are maintained spaced from each other by means of a novelbeam suspension system which minimizes mechanical contact, and henceheat transfer, between thetwo spheres.

In accordance with the preferred embodiment of the invention definedherein, the outer shell comprises two spherical segments, each less thana hemisphere and each welded to opposite circumferential edges of a bandconstituting the central zone of the outer sphere. Three arcuatesuspension beams are secured at equally spaced points to the bandextending laterally of the inner and outer sphere. One pair of spokes isassociated with each arcuate suspension beam and is adapted to befastened to fittings on the surface of the inner sphere for maintainingthe latter in dimensional balance at six points within the outer sphere.

The above and other features of novelty which characterize the inventionare pointed out with particularity in the claims annexed to and forminga part of this specification. For a better understanding of thisinvention, however, its advantages and specific objects attained withits use, reference is had to the accompanying drawing and descriptivematter in which is shown and described several illustrative embodimentsof the invention.

In the drawing:

Figure l is a side elevation partially broken away of one embodiment ofa liquid oxygen container embodying the suspension system of the presentinvention;

Figure 2 is a top plan view of the inner sphere of the container ofFigure 1, taken substantially on line 22 thereof;

Figure 3 is a perspective view with the band partially broken awayshowing the arcuate suspension beam in accordance with the invention;

Figure 4 is a view taken substantially on line 4-4 of Figure 2 showingthe spoke and fitting construction;

Figure 4A shows an alternative construction for the spoke and fitting;and

Figure 5 is a partial cross section illustrating the construction ofanother embodiment of the invention.

Referring now to the drawing, the specific illustrative embodiment shownin Figures 1 through 4A thereof comprises a thermally insulatedcontainer 10 having an outer sphere 12 and an inner sphere 14. Innersphere 14 is of smaller radial dimension than outer sphere 12 and isadapted to be supported within the outer sphere with a minimum ofphysical contact there'oetween.

Inner sphere 14 is suitable for holding and storing low temperaturematerials such as liquid oxygen which may be supplied to the innersphere through an inlet conduit 16 and removed from the inner spherethrough an outlet conduit 18. In the particular embodiment of theinvention shown in Figure l conduits to and 18 are connected in parallelto a single pipe 20 extending through outer shell 12 and into innershell 14. Conduit 16 advantageously may be connected to a filler valveand conduit 18 may be connected to a liquid check valve, such as areincluded in oxygen supply systems.

The liquid contents of inner sphere 14 may be indicated by a suitablegauge connected to electrical terminals 22 and 24 extending throughouter shell 12 and connected by conductors 26 and 28, respectively, to aprobe within the inner shell. A conduit 32 is provided on outer shell 12and is connected by piping 30 to the upper portion of inner shell 14.This permits desired pressures to be built up inside inner shell 14 toenable the container to function properly with suitable oxygen usingequipment such as oxygen masks and the like with which the con tainer isutilized.

. .It-.will be appreciated that since liquid oxygen 'vaporizes at atemperature of 183 C., it is necessary that a maximum degree of thermalinsulation be maintained between the inner and outer spheres; This isattained in accordance with the invention by means of a novel suspensionsystem comprising three arcuate suspension beams 36 fixed at 120 degreespacings to a band 34 Welded to the inner circumference of outer sphere12. Band 34 extends substantially around the inner circumference of theouter sphere with only a relatively small gap between its ends. As seenmost clearly in Figures 1 and 3, band 34 is of channel cross section andis positioned with its flanges facing inwardly towards the inner sphere.It is a feature of this invention that the longitudinal curvature ofband 34 is greater than the longitudinal curvature of sphere 12 suchthat when the band 34 is welded to the inner surface of the outer sphere12, the weld defines substantially single line contact between band 34and sphere 12. This is clearly shown, for example, in Figure 1 whereinthe single line contact between band 34 and sphere 12 is provided alongthe weld line 62.

Three arcuate suspension beams 36 are attached at equally spaced pointsto band 34. Each suspension beam 36 is of channel cross section and iswelded by means of lugs 38 and 40 on opposite flanges thereof to band34. Alternatively, each suspension beam 36 may be formed with extensionflanges extending outwardly from the beam in lieu of lugs 38 and 40. Inthis embodiment, the beam extension flanges would be welded to band 34to secure the beam thereto. The center of curvature of each suspensionbeam 36 is approximately the same as the centers of curvature of theinner and outer shells so that when the suspension beam is welded atright angles to band 34, the suspension beam is positioned intermediateand in parallel noncontacting relation with the inner and outer shells.

Each suspension beam 36 has at one end thereof an apertured flange 42and at the other end thereof an apertured flange 46. A collar 50 extendsoutwardly from the inner face of flange 42 and a collar 52 extendsoutwardly from the inner face of flange 46. An elongated spoke 54 havinga flared neck 56 at one end thereof is positioned through collar 50 andapertured flange 46 such that the collar engages the flared neck toprovide a stop for the spoke.

In the embodiment of the invention shown in Figure 4, the other end ofspoke 54 also is formed with a flared neck 58. The spoke isdimensionally balanced by drawing tube 63 into a fitting 66 whichadvantageously is welded to the outer surface of inner sphere 14. Thiscreates a tension on spoke 54 by virtue of the action of O-ring 68 intubing 60 on spoke neck 58. After balance is made tubing 60 is welded tofitting 66.

Alternatively, as shown in the embodiment of Figure 4A, tubular member60a is provided with an interior thread and the other end of spoke 54 isexternally threaded to enable the spoke to be adjusted as desired. Afterthe necessary adjustment has been made, the enlarged end of tubularmember 60a, abutting fitting-66 is welded to the fitting to fix thespoke firmly in position.

position by swaging collar 52 on flared neck 56 of the spoketo draw thespoke tight in assembly." After the suspension adjustment, collar 52 iswelded to fitting 46 assign to provide additional rigidity to the innersphere suspens1on.

When the above-described operation is completed, the two hemispherescomprising outer sphere 12 are welded together as designated at 62 inFigure l. The space between the inner and outer spheres then isevacuated to provide additional thermal insulation for inner sphere 14through a pinch off, shown covered by cap 64.

The preferred embodiment of the invention defined in this divisionalapplication is shown in Figure 5. As clearly disclosed therein, theouter sphere may comprise the spherical segments 70 and 72, each smallerthan a hemisphere. A band 74 of channel cross section forms the centralzone of the outer sphere. Advantageously, band 74 is placed with itsflanges facing outwardly, that is, away from the inner sphere and thecircumferential edges of spherical segments 70 and 72 are welded to theends of the flanges of band 74 such that the ends of the band are flushwith the spherical segments.

It will be appreciated that the construction illustrated in Figure 5gives rise to several important advantages. Thus, the center band 74,being of channel cross section, provides a means for mounting thecontainer by the use of straps and the like, in lieu of welded brackets,such as mounting brackets 48 shown in the embodiment of Figure 1.Thisserves to enhance the structural efliciency of the container sinceevery time a bracket is welded thereto, the chances of introducingleakage due to a faulty weld or induced stresses are increased.

Additionally, the use of the three piece outer sphere construction ofFigure 5 permits the use of the center band 74 as the structural memberfor the support of the inner sphere. This allows the shell thickness ofthe two spherical segments 70 and 72 to be minimized as these segmentsneed not be constructed as structural members. The resultant savings inweight and cost inherent in the construction of Figure 5 thus areevident.

A plurality of arcuate suspension beams 76, similar in construction .topreviously described arcuate suspension beams 36, are connected to band74. Advantageously, three suspension beams 76 are aflixed to band 74 atequally spaced points on the inner face of the band. Each suspensionbeam 76 is secured to band 74 by means of a stud 80 extending throughsuspension beam 76 and band 74 in tight clamping relation thereto. As inthe embodiment of Figures 1 through 4, a pair of apertured flanges isprovided at the ends of each suspension beam 76 for connection to spokesin the manner described above.

One alternative construction, in which stud 80 is eliminated, comprisesforming suspension beam 76 with extended flanges which are adapted to bemated and welded to central band 74. Another alternative construction inaccordance with the invention comprises the forming of suspension beams76 as integral parts of central band 74. Thus in this embodiment, thebeams and band are integrally formed, such as in a one piecestampingwhich is fashioned into a circle and finally welded with the beams atright angles to the spherical segments of the outer sphere.

It will be understood by those skilled in the art that band 74 may bewelded to spherical segments 70 and 72 with its flanges facing inwardlytoward the inner sphere. This is an alternative embodiment which hasbeen found to provide highly advantageous results.

To facilitate the welding operations, it is contemplated that the innerand outer spheres may be formed of stainless steel as the lattermaterial is impervious to'the diffusion of gases therethrough. Itfurther is contemplated that to enhance the thermal insulationcharacteristics of the novel container, the outer surface of innersphere and the inner surface of outer sphere 'will each be plated aswith copper, gold and the like, to increase their reflection qualities.

It will be understood by those skilled in the'art that modifications maybe made in the construction and arrangement of the parts of theabove-described suspension system liquid oxygen converter withoutdeparting from the real purpose and spirit of the invention and that itis intended to cover by the appended claims any modified forms ofstructures, circuits or use of equivalents which reasonably may beincluded within their scope.

What is claimed is:

1. A thermally insulated container for storing liquid oxygen and thelike comprising an inner sphere of given radial dimension, an outersphere of greater radial dimension completely enclosing said innersphere, said outer sphere comprising a pair of spherical segments eachsmaller than a hemisphere and a circular band, the oppositecircumferential edges of which are afiixed to the edges of said pair ofspherical segments, a plurality of laterally extending arcuatesuspension beams secured to the inner face of said circular band atevenly spaced apart points therearound, said arcuate suspension beamsbeing positioned parallel to the surfaces of said inner and outerspheres, a pair of fittings for each arcuate suspension beam secured tothe outer surface of said inner sphere, a fitting of each pair beingspaced from and in alignment with one end of its associated arcuatesuspension beam, a spoke disposed between each fitting and an end of anarcuate suspension beam and means for adjusting and maintaining saidspokes in tension between the arcuate suspension beam and the fitting tomaintain the inner sphere in dimensional balance within said outersphere.

2. A thermally insulated container comprising an inner sphere of givenradial dimension, an outer sphere of greater radial dimension completelyenclosing said inner sphere, said outer sphere comprising a pair ofspherical segments each smaller than a hemisphere and a circular band ofchannel cross section having flanges affixed to the edges of said pairof spherical segments, three transversely extending arcuate suspensionbeams uniformly spaced around said circular band and positionedintermediate and parallel to the surfaces of said inner and outerspheres, a fitting secured to said inner sphere in spaced alignment witheach end of said three arcuate suspension beams and a spoke between eachfitting and an end of each arcuate suspension beam for maintaining saidinner sphere in dimensional balance within said outer sphere.

3. A thermally insulated container assembly comprising an innercontainer of generally spherical configuration having a first radialdimension, an outer container of generally spherical configurationhaving a second radial dimension greater than said first radialdimension and completely enclosing said inner container, said outercontainer comprising a pair of spherical segments each smaller than ahemisphere and a circular central band having a pair of spaced apartcircumferential edges extending therearound and affixed respectively tothe circumferential edges of said pair of spherical segments, and meansconnected to said central band for maintaining said inner container indimensional balance within said outer container, said means comprising aplurality of arcuate extension beams uniformly spaced around saidcentral band and extending transversely thereto, each of said extensionbeams being adapted to receive inner container supporting means at theopposite ends thereof.

4. A thermally insulated container assembly in accordance with claim 3wherein said circular central band is formed with channel cross-section,and said arcuate extension beams are directly secured to said circularcentral band, to enhance the structunal efficiency of the container.

5. A thermally insulated container assembly in accordance with claim 3wherein said pair of spherical segments are formed with a shellthickness smaller than the shell thickness of said circular centralband, whereby only said central band serves as a structural member tosupport said inner container.

References Cited in the file of this patent UNITED STATES PATENTS2,467,428 Hansen et a1 Apr. 19, 1949 2,577,171 Wiggins Dec. 4, 19512,814,410 Hansen NOV. 26, 1957

